%pyproject_buildrequires macro now accepts multiple file names to load
additional dependencies from them.
New option -N was added to disable automatical generation of requirements
in case package does not use build system. Option -N cannot be used in
combination with options -r, -e, -t, -x.
Co-authored-by: Miro Hrončok <miro@hroncok.cz>
Related: rhbz#1950291
